Patenting Medical Treatments – An Overview

Healthcare is one of the most economically-important areas in which patents are granted.  In no small part, this is due to the great expense and risk involved in discovering, developing, trialling, gaining regulatory approval for, and ultimately commercialising new drugs and other forms of therapy. 

For better or worse, governments in the developed world have largely abdicated responsibility for research and development in this area, in favour of allowing private enterprise to bear the cost and risks.

In exchange, the patent system fulfils the role of ensuring that the companies taking on these risks are able to gain a commensurate economic benefit if, and when, their efforts pay off.  In fact, special treatment is provided in the patent laws of various countries for therapeutic inventions in particular, to ensure that the rewards outweigh the risks, including:

1. granting broad protection for new chemical compounds that have been shown to have at least one therapeutic use;
2. granting protection for known chemical compounds when they are first discovered to have at least one therapeutic use;
3. permitting further periods of more-limited protection for known chemical compounds when shown to be useful for a second, previously unknown, therapeutic purposes; and
4. extended terms of patent protection to compensate for time required to obtain regulatory approval to actually commence marketing of a therapeutic product (I have written about extensions of patent term on many previous occasions, and will not be covering them again here).

One aspect in which there is far less international uniformity is whether or not patents should be available for methods of treatment and/or diagnosis that are practised on the human body.  Indeed, in most countries medical treatment methods are considered unpatentable on policy grounds. 

As has been recently confirmed by the High Court, however, methods of medical treatment are patentable in Australia.  Such methods have also long been considered patentable in the US, although there has recently been concern that the decision of the Supreme Court in Mayo Collaborative Services v Prometheus Laboratories, Inc has imposed significant limitations on the types of treatment methods that can be patented.

The purpose of this article is not to get into the details, but rather to provide an overview of how patent laws protect (or not) medical treatments for readers who may be unfamiliar with this topic.

New Compounds, Broad Rights

If an inventor (or, more commonly, a team of inventors) discovers a new compound, along with at least one therapeutic use for the compound, then they may be awarded a patent on the compound itself.  More commonly, in fact, the initial patent will cover not just one compound, but a whole family of related compounds that can be expected to provide the new therapeutic effect.

Here, for example, is part of the original claim covering a compound called sildenafil – which you may know better by the brand name, Viagra:

You will see that the compound is claimed by providing a diagram of its chemical structure, in which each of the ‘R’s represents a substitutable group.  I have not reproduced the entire claim, which goes on to specify the acceptable groups that may sit in each of these positions on the molecule.

The patent specification describes how to make the compound, and in this sense it may seem unsurprising that the inventors were able to obtain a patent on the novel molecule itself.  However, the situation is not necessarily that simple.  The patent laws in most countries also require an invention to have some utility (you cannot have a patent just because you have made something for the first time if, in fact, you are unable to establish that it is useful for something), and require that the scope of the monopoly granted be commensurate with what has actually been invented.

The sildenafil patent satisfies the utility requirement, by explaining how the compound can be used to treat high blood pressure and angina.  Arguably, however, this is not enough to justify granting a monopoly on every possible use of every molecule in the class defined by the diagram above (including the one for which Viagra is most celebrated, and that is not even hinted at in the patent specification), which is what the original compound claim effectively achieves.

However, legislators, courts and participants in the pharmaceutical industry have all tacitly agreed not to look too closely at this technical issue of scope, on the basis that there is no real argument that the monopoly rights granted are a reasonable reward for the work that goes into discovering and developing an entire new compound for therapeutic use.

Known Compounds, Unknown Medical Uses

At the next level of protection, a chemical compound may already be known for some other purpose or reason, when a previously unrecognised therapeutic use is identified.

In a few countries, such as Australia and the US, a ‘first medical use’ invention may be protected as a method of treatment, i.e. by claiming ‘a method of treating [condition] in a subject, comprising administering to a subject in need of such treatment an effective amount of [compound]’.  While such a claim technically makes an infringer of the physician who prescribes the drug, in practice enforcement is against competing manufacturers on the basis that by supplying the compound for the claimed purpose they make themselves ‘indirect’ infringers of the claim.

In a wider range of countries (including across Europe, where method of treatment claims are expressly prohibited), a ‘first medical use’ can be claimed as ‘[compound] for use as a medicament/therapeutic substance’.  Such claims treat the words ‘for use’ as if they are an actual limitation that confers novelty and inventiveness upon the compound.  This is something of a ‘legal fiction’ in the sense that, in most other fields of endeavour, these words would be interpreted as meaning only ‘suitable for’, and thus impose no meaningful restriction on the compound, which is still the same old, known, substance.

In either form (and in some countries both can be used) the claims are quite broad in their effect, in that they do not impose any limitation on dosage or treatment regimes.  Any sale of the claimed compound for treatment of the identified condition – or, in the ‘first medical use’ form, any condition – will constitute a form of infringement.

Further Medical Uses, and Further Tricks of the Trade

Matters become trickier if a new therapeutic use is discovered for a compound that is already known to have one or more existing therapeutic uses.  Sometimes, the new use will involve a different manner of administration and/or a new treatment or dosage regime.  In any event, the therapeutic effectiveness of the compound for the new use still needs to be demonstrated and approved before it can be marketed for that purpose.  Therefore, some form of further protection remains desirable as an incentive for private companies to work on finding additional therapeutic applications of known compounds.

One way in which the courts and administrators in many countries have consented to protect ‘second medical use’ inventions is via the so-called ‘Swiss’ style of claim.  Such claims take the form ‘[compound] for use in the manufacture of a medicament for treatment of [new condition].’ 

Again, this involves a form of legal fiction, in that according to the normal rules of interpretation the scope of this claim is simply the compound itself, on the basis that it is ‘suitable for’ manufacturing the medicament in question.  In practice, however, Swiss-style claims are treated as if they cover any and every method of making a medicament of any kind that includes the compound as an active ingredient, and with the intention of it being used to treat the new condition.

More recently, the European Patent Convention was updated such that second and further medical uses of compounds can be claimed simply as, e.g., ‘[compound] for use in the treatment of [new condition]’ (see Article 54(4) EPC).  As a result, Swiss-style claims are now regarded as invalid in new European patent applications, which prevents applicants from creating confusion by effectively claiming the same invention in different ways that may, or may not, be of different scope!

In some countries a subsequent therapeutic use can be claimed in multiple different ways, e.g. the Swiss form, the ‘new use’ form, and/or as a method of treatment, which really allows multiple bases to be covered!

Methods of Treatment – To Allow Patents or Not?

A common policy justification for excluding methods of medical treatment from patentability is the concern that medical practitioners may be restricted in providing health- or life-saving therapies by the existence of relevant patent monopolies.  This is why, for example, Article 53 EPC expressly excludes from patentability in Europe ‘methods for treatment of the human or animal body by surgery or therapy and diagnostic methods practised on the human or animal body’.

Similarly, medical practices may be regarded as essentially non-economic, or not the kind of commercially-useful processes that the patent system is intended to protect.  Thus the Canadian courts have regarded methods of treatment as lacking ‘utility’, while the New Zealand courts (under the old Patents Act 1953) found that such methods were not proper subject matter for a patent under the ‘manner of manufacture’ test. 

In Australia, although patents on methods of treatment had been granted for many years, there was some doubt as to whether they were valid ‘manners of manufacture’, until the High Court settled the question in December 2013, when the Chief Justice stated that:

The exclusion from patentability of methods of medical treatment represents an anomaly for which no clear and consistent foundation has been enunciated. Whatever views may have held in the past, methods of medical treatment, particularly the use of pharmaceutical drugs, cannot today be conceived as "essentially non-economic".

Section 16 of the New Zealand Patents Act 2013 now expressly provides that ‘an invention of a method of treatment of human beings by surgery or therapy is not a patentable invention’ and that ‘an invention of a method of diagnosis practised on human beings is not a patentable invention.’  Notably, unlike Europe the restriction does not apply to treatment of animals which, presumably, recognises the economic utility of the work of veterinarians in a country with a significant agricultural industry.

In the US, while methods of medical treatment are patentable, there is defence in the patent law (35 USC 287(c)) such that ‘with respect to a medical practitioner’s performance of a medical activity that constitutes an infringement … the [penalties for infringement] shall not apply against the medical practitioner or against a related health care entity with respect to such medical activity.’

In Australia, a concern that medical practitioners should perhaps not be subject to potential patent infringement action for engaging in medical activity remains unresolved.  In the recent High Court case, to which I have already referred, three of the Judges joined in a concurring opinion in which they expressed the view that there is:

… a distinction which can be acknowledged between a method of medical treatment which involves a hitherto unknown therapeutic use of a pharmaceutical (having prior therapeutic uses) and the activities or procedures of doctors (and other medical staff) when physically treating patients. Although it is unnecessary to decide the point, or to seek to characterise such activities or procedures exhaustively, speaking generally they are, in the language of the NRDC Case, ‘essentially non-economic’ and, in the language of the EPC and the Patents Act 1977 (UK), they are not ‘susceptible’ or ‘capable’ of industrial application.

Conclusion – Is Personalised Medicine the New Patent Frontier?

In short, we can see that pharmaceutical substances, and medical treatments more generally, receive certain kinds of ‘special treatment’ under national and international patent laws.

There are, historically, good reasons for this, in that the economic rewards provided by the patent system have needed to be particularly potent to provide incentives for private companies to take on the task of discovering and developing new drugs and new treatments.

Broadly speaking, a line is drawn in most countries between the activities of commercial research and development enterprises and those of treatment hospitals and individual practitioners, although the precise location and nature of this line varies from country-to-country.

Increasingly, however, the advent of ‘personalised medicine’ is blurring the boundaries between the work of drug and biotechnology companies, and the activities of medical practitioners treating their patients.  Whether the balance between patent rights and the freedom of practitioners to practise remains appropriate is uncertain.  Developments such as the US Supreme Court decisions in Mayo v Prometheus and Association for Molecular Pathology v Myriad Genetics along with the pending Australian High Court decision in the local Myriad case suggest that this is still an emerging contested area in patent law around the world.

Tags: Patent law, Patentable subject matter, Pharmaceuticals, Public policy